An X-ray CT apparatus irradiates a subject with X-rays generated by an X-ray tube, detects X-rays transmitted through the subject, and provides image data on the subject generated on the basis of the detection signal. Such X-ray CT apparatuses play an important role in medical practices such as diagnosis and treatment. The X-ray CT apparatus includes a gantry having an X-ray irradiator that irradiates a subject placed on a tabletop with X-rays and an X-ray detector that detects X-rays transmitted through the subject. The gantry has a cylindrical opening. The tabletop is moved to transfer the subject into the opening. Then, while rotating around the subject, the X-ray irradiator including an X-ray tube irradiates the subject with X rays and the X-ray detector detects X-rays transmitted through the subject. In this way, the CT scanning of the subject is performed.
In this regard, there is known an aid for holding a part of a subject placed on a tabletop in CT scanning, such as a headrest for holding the head and an armrest for holding the arm.
The aid has connecting portions, and the tabletop has connection holes provided in an edge portion on the gantry side and arranged along a longitudinal direction of the tabletop. The aid is moved from one side of the tabletop to the longitudinal edge portion on the gantry side and is fixed to the tabletop by inserting the connecting portions into the connection holes. When the scanning is completed, the tabletop with the aid fixed thereto is lowered to a height that is lower than the opening of the gantry and that makes it easy for the subject to get on and off the tabletop (hereinafter, boarding height). After the subject gets off the tabletop, the aid is replaced with an aid suitable for a scanning part of the next subject as necessary.
Meanwhile, generally there is not a sufficient space between the gantry and the edge portion of the tabletop on the gantry side. For this reason, when the tabletop stays at the boarding height lower than the opening of the gantry, the gantry positioned close to the tabletop hinders the aid from being moved in a direction opposite to the direction in which the aid is inserted. Consequently, the aid cannot be removed. Thus, after completion of the scanning, in a case where the aid needs to be removed from the tabletop, or where an aid needs to be attached to the tabletop for the next scanning, the tabletop has to be raised to such a height around the opening that any hindrance can be avoided. Then, after the aid is attached or detached, the tabletop has to be lowered again to the boarding height. This brings about a problem that operations to move the tabletop vertically are needed and require a lot of work.